Why duolingo app on android and iphone has difference??

Me and my friend are using duolingo to learn spanish. on her iphone she could find the explanation about every chapters grammar. But my android app doesnt have that book icon. can someone explain why?

July 19, 2018


Different mobile app developer teams.

IOS is their favourite "playing plattform", where they test new things like Health, gems, Clubs "find me a random club",...

Reason (probably): You can not simply rollback to a previous version if you do not like the changes.

IOS: "Grammar notes in app but not online":

July 19, 2018
Learn a language in just 5 minutes a day. For free.